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 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.lang;

import java.io.*;
import java.util.StringTokenizer;
import sun.reflect.CallerSensitive;
import sun.reflect.Reflection;

/**
 * Every Java application has a single instance of class
 * <code>Runtime</code> that allows the application to interface with
 * the environment in which the application is running. The current
 * runtime can be obtained from the <code>getRuntime</code> method.
 * <p>
 * An application cannot create its own instance of this class.
 *
 * @author unascribed
 * @see java.lang.Runtime#getRuntime()
 * @since JDK1.0
 */

public class Runtime {

  private static Runtime currentRuntime = new Runtime();

  /**
   * Returns the runtime object associated with the current Java application.
   * Most of the methods of class <code>Runtime</code> are instance
   * methods and must be invoked with respect to the current runtime object.
   *
   * @return the <code>Runtime</code> object associated with the current Java application.
   */
  public static Runtime getRuntime() {
    return currentRuntime;
  }

  /**
   * Don't let anyone else instantiate this class
   */
  private Runtime() {
  }

  /**
   * Terminates the currently running Java virtual machine by initiating its
   * shutdown sequence.  This method never returns normally.  The argument
   * serves as a status code; by convention, a nonzero status code indicates
   * abnormal termination.
   *
   * <p> The virtual machine's shutdown sequence consists of two phases.  In
   * the first phase all registered {@link #addShutdownHook shutdown hooks},
   * if any, are started in some unspecified order and allowed to run
   * concurrently until they finish.  In the second phase all uninvoked
   * finalizers are run if {@link #runFinalizersOnExit finalization-on-exit}
   * has been enabled.  Once this is done the virtual machine {@link #halt
   * halts}.
   *
   * <p> If this method is invoked after the virtual machine has begun its
   * shutdown sequence then if shutdown hooks are being run this method will
   * block indefinitely.  If shutdown hooks have already been run and on-exit
   * finalization has been enabled then this method halts the virtual machine
   * with the given status code if the status is nonzero; otherwise, it
   * blocks indefinitely.
   *
   * <p> The <tt>{@link System#exit(int) System.exit}</tt> method is the
   * conventional and convenient means of invoking this method. <p>
   *
   * @param status Termination status.  By convention, a nonzero status code indicates abnormal
   * termination.
   * @throws SecurityException If a security manager is present and its <tt>{@link
   * SecurityManager#checkExit checkExit}</tt> method does not permit exiting with the specified
   * status
   * @see java.lang.SecurityException
   * @see java.lang.SecurityManager#checkExit(int)
   * @see #addShutdownHook
   * @see #removeShutdownHook
   * @see #runFinalizersOnExit
   * @see #halt(int)
   */
  public void exit(int status) {
    SecurityManager security = System.getSecurityManager();
    if (security != null) {
      security.checkExit(status);
    }
    Shutdown.exit(status);
  }

  /**
   * Registers a new virtual-machine shutdown hook.
   *
   * <p> The Java virtual machine <i>shuts down</i> in response to two kinds
   * of events:
   *
   * <ul>
   *
   * <li> The program <i>exits</i> normally, when the last non-daemon
   * thread exits or when the <tt>{@link #exit exit}</tt> (equivalently,
   * {@link System#exit(int) System.exit}) method is invoked, or
   *
   * <li> The virtual machine is <i>terminated</i> in response to a
   * user interrupt, such as typing <tt>^C</tt>, or a system-wide event,
   * such as user logoff or system shutdown.
   *
   * </ul>
   *
   * <p> A <i>shutdown hook</i> is simply an initialized but unstarted
   * thread.  When the virtual machine begins its shutdown sequence it will
   * start all registered shutdown hooks in some unspecified order and let
   * them run concurrently.  When all the hooks have finished it will then
   * run all uninvoked finalizers if finalization-on-exit has been enabled.
   * Finally, the virtual machine will halt.  Note that daemon threads will
   * continue to run during the shutdown sequence, as will non-daemon threads
   * if shutdown was initiated by invoking the <tt>{@link #exit exit}</tt>
   * method.
   *
   * <p> Once the shutdown sequence has begun it can be stopped only by
   * invoking the <tt>{@link #halt halt}</tt> method, which forcibly
   * terminates the virtual machine.
   *
   * <p> Once the shutdown sequence has begun it is impossible to register a
   * new shutdown hook or de-register a previously-registered hook.
   * Attempting either of these operations will cause an
   * <tt>{@link IllegalStateException}</tt> to be thrown.
   *
   * <p> Shutdown hooks run at a delicate time in the life cycle of a virtual
   * machine and should therefore be coded defensively.  They should, in
   * particular, be written to be thread-safe and to avoid deadlocks insofar
   * as possible.  They should also not rely blindly upon services that may
   * have registered their own shutdown hooks and therefore may themselves in
   * the process of shutting down.  Attempts to use other thread-based
   * services such as the AWT event-dispatch thread, for example, may lead to
   * deadlocks.
   *
   * <p> Shutdown hooks should also finish their work quickly.  When a
   * program invokes <tt>{@link #exit exit}</tt> the expectation is
   * that the virtual machine will promptly shut down and exit.  When the
   * virtual machine is terminated due to user logoff or system shutdown the
   * underlying operating system may only allow a fixed amount of time in
   * which to shut down and exit.  It is therefore inadvisable to attempt any
   * user interaction or to perform a long-running computation in a shutdown
   * hook.
   *
   * <p> Uncaught exceptions are handled in shutdown hooks just as in any
   * other thread, by invoking the <tt>{@link ThreadGroup#uncaughtException
   * uncaughtException}</tt> method of the thread's <tt>{@link
   * ThreadGroup}</tt> object.  The default implementation of this method
   * prints the exception's stack trace to <tt>{@link System#err}</tt> and
   * terminates the thread; it does not cause the virtual machine to exit or
   * halt.
   *
   * <p> In rare circumstances the virtual machine may <i>abort</i>, that is,
   * stop running without shutting down cleanly.  This occurs when the
   * virtual machine is terminated externally, for example with the
   * <tt>SIGKILL</tt> signal on Unix or the <tt>TerminateProcess</tt> call on
   * Microsoft Windows.  The virtual machine may also abort if a native
   * method goes awry by, for example, corrupting internal data structures or
   * attempting to access nonexistent memory.  If the virtual machine aborts
   * then no guarantee can be made about whether or not any shutdown hooks
   * will be run. <p>
   *
   * @param hook An initialized but unstarted <tt>{@link Thread}</tt> object
   * @throws IllegalArgumentException If the specified hook has already been registered, or if it
   * can be determined that the hook is already running or has already been run
   * @throws IllegalStateException If the virtual machine is already in the process of shutting
   * down
   * @throws SecurityException If a security manager is present and it denies <tt>{@link
   * RuntimePermission}("shutdownHooks")</tt>
   * @see #removeShutdownHook
   * @see #halt(int)
   * @see #exit(int)
   * @since 1.3
   */
  public void addShutdownHook(Thread hook) {
    SecurityManager sm = System.getSecurityManager();
    if (sm != null) {
      sm.checkPermission(new RuntimePermission("shutdownHooks"));
    }
    ApplicationShutdownHooks.add(hook);
  }

  /**
   * De-registers a previously-registered virtual-machine shutdown hook. <p>
   *
   * @param hook the hook to remove
   * @return <tt>true</tt> if the specified hook had previously been registered and was successfully
   * de-registered, <tt>false</tt> otherwise.
   * @throws IllegalStateException If the virtual machine is already in the process of shutting
   * down
   * @throws SecurityException If a security manager is present and it denies <tt>{@link
   * RuntimePermission}("shutdownHooks")</tt>
   * @see #addShutdownHook
   * @see #exit(int)
   * @since 1.3
   */
  public boolean removeShutdownHook(Thread hook) {
    SecurityManager sm = System.getSecurityManager();
    if (sm != null) {
      sm.checkPermission(new RuntimePermission("shutdownHooks"));
    }
    return ApplicationShutdownHooks.remove(hook);
  }

  /**
   * Forcibly terminates the currently running Java virtual machine.  This
   * method never returns normally.
   *
   * <p> This method should be used with extreme caution.  Unlike the
   * <tt>{@link #exit exit}</tt> method, this method does not cause shutdown
   * hooks to be started and does not run uninvoked finalizers if
   * finalization-on-exit has been enabled.  If the shutdown sequence has
   * already been initiated then this method does not wait for any running
   * shutdown hooks or finalizers to finish their work. <p>
   *
   * @param status Termination status.  By convention, a nonzero status code indicates abnormal
   * termination.  If the <tt>{@link Runtime#exit exit}</tt> (equivalently, <tt>{@link
   * System#exit(int) System.exit}</tt>) method has already been invoked then this status code will
   * override the status code passed to that method.
   * @throws SecurityException If a security manager is present and its <tt>{@link
   * SecurityManager#checkExit checkExit}</tt> method does not permit an exit with the specified
   * status
   * @see #exit
   * @see #addShutdownHook
   * @see #removeShutdownHook
   * @since 1.3
   */
  public void halt(int status) {
    SecurityManager sm = System.getSecurityManager();
    if (sm != null) {
      sm.checkExit(status);
    }
    Shutdown.halt(status);
  }

  /**
   * Enable or disable finalization on exit; doing so specifies that the
   * finalizers of all objects that have finalizers that have not yet been
   * automatically invoked are to be run before the Java runtime exits.
   * By default, finalization on exit is disabled.
   *
   * <p>If there is a security manager,
   * its <code>checkExit</code> method is first called
   * with 0 as its argument to ensure the exit is allowed.
   * This could result in a SecurityException.
   *
   * @param value true to enable finalization on exit, false to disable
   * @throws SecurityException if a security manager exists and its <code>checkExit</code> method
   * doesn't allow the exit.
   * @see java.lang.Runtime#exit(int)
   * @see java.lang.Runtime#gc()
   * @see java.lang.SecurityManager#checkExit(int)
   * @since JDK1.1
   * @deprecated This method is inherently unsafe.  It may result in finalizers being called on live
   * objects while other threads are concurrently manipulating those objects, resulting in erratic
   * behavior or deadlock.
   */
  @Deprecated
  public static void runFinalizersOnExit(boolean value) {
    SecurityManager security = System.getSecurityManager();
    if (security != null) {
      try {
        security.checkExit(0);
      } catch (SecurityException e) {
        throw new SecurityException("runFinalizersOnExit");
      }
    }
    Shutdown.setRunFinalizersOnExit(value);
  }

  /**
   * Executes the specified string command in a separate process.
   *
   * <p>This is a convenience method.  An invocation of the form
   * <tt>exec(command)</tt>
   * behaves in exactly the same way as the invocation
   * <tt>{@link #exec(String, String[], File) exec}(command, null, null)</tt>.
   *
   * @param command a specified system command.
   * @return A new {@link Process} object for managing the subprocess
   * @throws SecurityException If a security manager exists and its {@link SecurityManager#checkExec
   * checkExec} method doesn't allow creation of the subprocess
   * @throws IOException If an I/O error occurs
   * @throws NullPointerException If <code>command</code> is <code>null</code>
   * @throws IllegalArgumentException If <code>command</code> is empty
   * @see #exec(String[], String[], File)
   * @see ProcessBuilder
   */
  public Process exec(String command) throws IOException {
    return exec(command, null, null);
  }

  /**
   * Executes the specified string command in a separate process with the
   * specified environment.
   *
   * <p>This is a convenience method.  An invocation of the form
   * <tt>exec(command, envp)</tt>
   * behaves in exactly the same way as the invocation
   * <tt>{@link #exec(String, String[], File) exec}(command, envp, null)</tt>.
   *
   * @param command a specified system command.
   * @param envp array of strings, each element of which has environment variable settings in the
   * format <i>name</i>=<i>value</i>, or <tt>null</tt> if the subprocess should inherit the
   * environment of the current process.
   * @return A new {@link Process} object for managing the subprocess
   * @throws SecurityException If a security manager exists and its {@link SecurityManager#checkExec
   * checkExec} method doesn't allow creation of the subprocess
   * @throws IOException If an I/O error occurs
   * @throws NullPointerException If <code>command</code> is <code>null</code>, or one of the
   * elements of <code>envp</code> is <code>null</code>
   * @throws IllegalArgumentException If <code>command</code> is empty
   * @see #exec(String[], String[], File)
   * @see ProcessBuilder
   */
  public Process exec(String command, String[] envp) throws IOException {
    return exec(command, envp, null);
  }

  /**
   * Executes the specified string command in a separate process with the
   * specified environment and working directory.
   *
   * <p>This is a convenience method.  An invocation of the form
   * <tt>exec(command, envp, dir)</tt>
   * behaves in exactly the same way as the invocation
   * <tt>{@link #exec(String[], String[], File) exec}(cmdarray, envp, dir)</tt>,
   * where <code>cmdarray</code> is an array of all the tokens in
   * <code>command</code>.
   *
   * <p>More precisely, the <code>command</code> string is broken
   * into tokens using a {@link StringTokenizer} created by the call
   * <code>new {@link StringTokenizer}(command)</code> with no
   * further modification of the character categories.  The tokens
   * produced by the tokenizer are then placed in the new string
   * array <code>cmdarray</code>, in the same order.
   *
   * @param command a specified system command.
   * @param envp array of strings, each element of which has environment variable settings in the
   * format <i>name</i>=<i>value</i>, or <tt>null</tt> if the subprocess should inherit the
   * environment of the current process.
   * @param dir the working directory of the subprocess, or <tt>null</tt> if the subprocess should
   * inherit the working directory of the current process.
   * @return A new {@link Process} object for managing the subprocess
   * @throws SecurityException If a security manager exists and its {@link SecurityManager#checkExec
   * checkExec} method doesn't allow creation of the subprocess
   * @throws IOException If an I/O error occurs
   * @throws NullPointerException If <code>command</code> is <code>null</code>, or one of the
   * elements of <code>envp</code> is <code>null</code>
   * @throws IllegalArgumentException If <code>command</code> is empty
   * @see ProcessBuilder
   * @since 1.3
   */
  public Process exec(String command, String[] envp, File dir)
      throws IOException {
    if (command.length() == 0) {
      throw new IllegalArgumentException("Empty command");
    }

    StringTokenizer st = new StringTokenizer(command);
    String[] cmdarray = new String[st.countTokens()];
    for (int i = 0; st.hasMoreTokens(); i++) {
      cmdarray[i] = st.nextToken();
    }
    return exec(cmdarray, envp, dir);
  }

  /**
   * Executes the specified command and arguments in a separate process.
   *
   * <p>This is a convenience method.  An invocation of the form
   * <tt>exec(cmdarray)</tt>
   * behaves in exactly the same way as the invocation
   * <tt>{@link #exec(String[], String[], File) exec}(cmdarray, null, null)</tt>.
   *
   * @param cmdarray array containing the command to call and its arguments.
   * @return A new {@link Process} object for managing the subprocess
   * @throws SecurityException If a security manager exists and its {@link SecurityManager#checkExec
   * checkExec} method doesn't allow creation of the subprocess
   * @throws IOException If an I/O error occurs
   * @throws NullPointerException If <code>cmdarray</code> is <code>null</code>, or one of the
   * elements of <code>cmdarray</code> is <code>null</code>
   * @throws IndexOutOfBoundsException If <code>cmdarray</code> is an empty array (has length
   * <code>0</code>)
   * @see ProcessBuilder
   */
  public Process exec(String cmdarray[]) throws IOException {
    return exec(cmdarray, null, null);
  }

  /**
   * Executes the specified command and arguments in a separate process
   * with the specified environment.
   *
   * <p>This is a convenience method.  An invocation of the form
   * <tt>exec(cmdarray, envp)</tt>
   * behaves in exactly the same way as the invocation
   * <tt>{@link #exec(String[], String[], File) exec}(cmdarray, envp, null)</tt>.
   *
   * @param cmdarray array containing the command to call and its arguments.
   * @param envp array of strings, each element of which has environment variable settings in the
   * format <i>name</i>=<i>value</i>, or <tt>null</tt> if the subprocess should inherit the
   * environment of the current process.
   * @return A new {@link Process} object for managing the subprocess
   * @throws SecurityException If a security manager exists and its {@link SecurityManager#checkExec
   * checkExec} method doesn't allow creation of the subprocess
   * @throws IOException If an I/O error occurs
   * @throws NullPointerException If <code>cmdarray</code> is <code>null</code>, or one of the
   * elements of <code>cmdarray</code> is <code>null</code>, or one of the elements of
   * <code>envp</code> is <code>null</code>
   * @throws IndexOutOfBoundsException If <code>cmdarray</code> is an empty array (has length
   * <code>0</code>)
   * @see ProcessBuilder
   */
  public Process exec(String[] cmdarray, String[] envp) throws IOException {
    return exec(cmdarray, envp, null);
  }


  /**
   * Executes the specified command and arguments in a separate process with
   * the specified environment and working directory.
   *
   * <p>Given an array of strings <code>cmdarray</code>, representing the
   * tokens of a command line, and an array of strings <code>envp</code>,
   * representing "environment" variable settings, this method creates
   * a new process in which to execute the specified command.
   *
   * <p>This method checks that <code>cmdarray</code> is a valid operating
   * system command.  Which commands are valid is system-dependent,
   * but at the very least the command must be a non-empty list of
   * non-null strings.
   *
   * <p>If <tt>envp</tt> is <tt>null</tt>, the subprocess inherits the
   * environment settings of the current process.
   *
   * <p>A minimal set of system dependent environment variables may
   * be required to start a process on some operating systems.
   * As a result, the subprocess may inherit additional environment variable
   * settings beyond those in the specified environment.
   *
   * <p>{@link ProcessBuilder#start()} is now the preferred way to
   * start a process with a modified environment.
   *
   * <p>The working directory of the new subprocess is specified by <tt>dir</tt>.
   * If <tt>dir</tt> is <tt>null</tt>, the subprocess inherits the
   * current working directory of the current process.
   *
   * <p>If a security manager exists, its
   * {@link SecurityManager#checkExec checkExec}
   * method is invoked with the first component of the array
   * <code>cmdarray</code> as its argument. This may result in a
   * {@link SecurityException} being thrown.
   *
   * <p>Starting an operating system process is highly system-dependent.
   * Among the many things that can go wrong are:
   * <ul>
   * <li>The operating system program file was not found.
   * <li>Access to the program file was denied.
   * <li>The working directory does not exist.
   * </ul>
   *
   * <p>In such cases an exception will be thrown.  The exact nature
   * of the exception is system-dependent, but it will always be a
   * subclass of {@link IOException}.
   *
   * @param cmdarray array containing the command to call and its arguments.
   * @param envp array of strings, each element of which has environment variable settings in the
   * format <i>name</i>=<i>value</i>, or <tt>null</tt> if the subprocess should inherit the
   * environment of the current process.
   * @param dir the working directory of the subprocess, or <tt>null</tt> if the subprocess should
   * inherit the working directory of the current process.
   * @return A new {@link Process} object for managing the subprocess
   * @throws SecurityException If a security manager exists and its {@link SecurityManager#checkExec
   * checkExec} method doesn't allow creation of the subprocess
   * @throws IOException If an I/O error occurs
   * @throws NullPointerException If <code>cmdarray</code> is <code>null</code>, or one of the
   * elements of <code>cmdarray</code> is <code>null</code>, or one of the elements of
   * <code>envp</code> is <code>null</code>
   * @throws IndexOutOfBoundsException If <code>cmdarray</code> is an empty array (has length
   * <code>0</code>)
   * @see ProcessBuilder
   * @since 1.3
   */
  public Process exec(String[] cmdarray, String[] envp, File dir)
      throws IOException {
    return new ProcessBuilder(cmdarray)
        .environment(envp)
        .directory(dir)
        .start();
  }

  /**
   * Returns the number of processors available to the Java virtual machine.
   *
   * <p> This value may change during a particular invocation of the virtual
   * machine.  Applications that are sensitive to the number of available
   * processors should therefore occasionally poll this property and adjust
   * their resource usage appropriately. </p>
   *
   * @return the maximum number of processors available to the virtual machine; never smaller than
   * one
   * @since 1.4
   */
  public native int availableProcessors();

  /**
   * Returns the amount of free memory in the Java Virtual Machine.
   * Calling the
   * <code>gc</code> method may result in increasing the value returned
   * by <code>freeMemory.</code>
   *
   * @return an approximation to the total amount of memory currently available for future allocated
   * objects, measured in bytes.
   */
  public native long freeMemory();

  /**
   * Returns the total amount of memory in the Java virtual machine.
   * The value returned by this method may vary over time, depending on
   * the host environment.
   * <p>
   * Note that the amount of memory required to hold an object of any
   * given type may be implementation-dependent.
   *
   * @return the total amount of memory currently available for current and future objects, measured
   * in bytes.
   */
  public native long totalMemory();

  /**
   * Returns the maximum amount of memory that the Java virtual machine will
   * attempt to use.  If there is no inherent limit then the value {@link
   * java.lang.Long#MAX_VALUE} will be returned.
   *
   * @return the maximum amount of memory that the virtual machine will attempt to use, measured in
   * bytes
   * @since 1.4
   */
  public native long maxMemory();

  /**
   * Runs the garbage collector.
   * Calling this method suggests that the Java virtual machine expend
   * effort toward recycling unused objects in order to make the memory
   * they currently occupy available for quick reuse. When control
   * returns from the method call, the virtual machine has made
   * its best effort to recycle all discarded objects.
   * <p>
   * The name <code>gc</code> stands for "garbage
   * collector". The virtual machine performs this recycling
   * process automatically as needed, in a separate thread, even if the
   * <code>gc</code> method is not invoked explicitly.
   * <p>
   * The method {@link System#gc()} is the conventional and convenient
   * means of invoking this method.
   */
  public native void gc();

  /* Wormhole for calling java.lang.ref.Finalizer.runFinalization */
  private static native void runFinalization0();

  /**
   * Runs the finalization methods of any objects pending finalization.
   * Calling this method suggests that the Java virtual machine expend
   * effort toward running the <code>finalize</code> methods of objects
   * that have been found to be discarded but whose <code>finalize</code>
   * methods have not yet been run. When control returns from the
   * method call, the virtual machine has made a best effort to
   * complete all outstanding finalizations.
   * <p>
   * The virtual machine performs the finalization process
   * automatically as needed, in a separate thread, if the
   * <code>runFinalization</code> method is not invoked explicitly.
   * <p>
   * The method {@link System#runFinalization()} is the conventional
   * and convenient means of invoking this method.
   *
   * @see java.lang.Object#finalize()
   */
  public void runFinalization() {
    runFinalization0();
  }

  /**
   * Enables/Disables tracing of instructions.
   * If the <code>boolean</code> argument is <code>true</code>, this
   * method suggests that the Java virtual machine emit debugging
   * information for each instruction in the virtual machine as it
   * is executed. The format of this information, and the file or other
   * output stream to which it is emitted, depends on the host environment.
   * The virtual machine may ignore this request if it does not support
   * this feature. The destination of the trace output is system
   * dependent.
   * <p>
   * If the <code>boolean</code> argument is <code>false</code>, this
   * method causes the virtual machine to stop performing the
   * detailed instruction trace it is performing.
   *
   * @param on <code>true</code> to enable instruction tracing; <code>false</code> to disable this
   * feature.
   */
  public native void traceInstructions(boolean on);

  /**
   * Enables/Disables tracing of method calls.
   * If the <code>boolean</code> argument is <code>true</code>, this
   * method suggests that the Java virtual machine emit debugging
   * information for each method in the virtual machine as it is
   * called. The format of this information, and the file or other output
   * stream to which it is emitted, depends on the host environment. The
   * virtual machine may ignore this request if it does not support
   * this feature.
   * <p>
   * Calling this method with argument false suggests that the
   * virtual machine cease emitting per-call debugging information.
   *
   * @param on <code>true</code> to enable instruction tracing; <code>false</code> to disable this
   * feature.
   */
  public native void traceMethodCalls(boolean on);

  /**
   * Loads the native library specified by the filename argument.  The filename
   * argument must be an absolute path name.
   * (for example
   * <code>Runtime.getRuntime().load("/home/avh/lib/libX11.so");</code>).
   *
   * If the filename argument, when stripped of any platform-specific library
   * prefix, path, and file extension, indicates a library whose name is,
   * for example, L, and a native library called L is statically linked
   * with the VM, then the JNI_OnLoad_L function exported by the library
   * is invoked rather than attempting to load a dynamic library.
   * A filename matching the argument does not have to exist in the file
   * system. See the JNI Specification for more details.
   *
   * Otherwise, the filename argument is mapped to a native library image in
   * an implementation-dependent manner.
   * <p>
   * First, if there is a security manager, its <code>checkLink</code>
   * method is called with the <code>filename</code> as its argument.
   * This may result in a security exception.
   * <p>
   * This is similar to the method {@link #loadLibrary(String)}, but it
   * accepts a general file name as an argument rather than just a library
   * name, allowing any file of native code to be loaded.
   * <p>
   * The method {@link System#load(String)} is the conventional and
   * convenient means of invoking this method.
   *
   * @param filename the file to load.
   * @throws SecurityException if a security manager exists and its <code>checkLink</code> method
   * doesn't allow loading of the specified dynamic library
   * @throws UnsatisfiedLinkError if either the filename is not an absolute path name, the native
   * library is not statically linked with the VM, or the library cannot be mapped to a native
   * library image by the host system.
   * @throws NullPointerException if <code>filename</code> is <code>null</code>
   * @see java.lang.Runtime#getRuntime()
   * @see java.lang.SecurityException
   * @see java.lang.SecurityManager#checkLink(java.lang.String)
   */
  @CallerSensitive
  public void load(String filename) {
    load0(Reflection.getCallerClass(), filename);
  }

  synchronized void load0(Class<?> fromClass, String filename) {
    SecurityManager security = System.getSecurityManager();
    if (security != null) {
      security.checkLink(filename);
    }
    if (!(new File(filename).isAbsolute())) {
      throw new UnsatisfiedLinkError(
          "Expecting an absolute path of the library: " + filename);
    }
    ClassLoader.loadLibrary(fromClass, filename, true);
  }

  /**
   * Loads the native library specified by the <code>libname</code>
   * argument.  The <code>libname</code> argument must not contain any platform
   * specific prefix, file extension or path. If a native library
   * called <code>libname</code> is statically linked with the VM, then the
   * JNI_OnLoad_<code>libname</code> function exported by the library is invoked.
   * See the JNI Specification for more details.
   *
   * Otherwise, the libname argument is loaded from a system library
   * location and mapped to a native library image in an implementation-
   * dependent manner.
   * <p>
   * First, if there is a security manager, its <code>checkLink</code>
   * method is called with the <code>libname</code> as its argument.
   * This may result in a security exception.
   * <p>
   * The method {@link System#loadLibrary(String)} is the conventional
   * and convenient means of invoking this method. If native
   * methods are to be used in the implementation of a class, a standard
   * strategy is to put the native code in a library file (call it
   * <code>LibFile</code>) and then to put a static initializer:
   * <blockquote><pre>
   * static { System.loadLibrary("LibFile"); }
   * </pre></blockquote>
   * within the class declaration. When the class is loaded and
   * initialized, the necessary native code implementation for the native
   * methods will then be loaded as well.
   * <p>
   * If this method is called more than once with the same library
   * name, the second and subsequent calls are ignored.
   *
   * @param libname the name of the library.
   * @throws SecurityException if a security manager exists and its <code>checkLink</code> method
   * doesn't allow loading of the specified dynamic library
   * @throws UnsatisfiedLinkError if either the libname argument contains a file path, the native
   * library is not statically linked with the VM,  or the library cannot be mapped to a native
   * library image by the host system.
   * @throws NullPointerException if <code>libname</code> is <code>null</code>
   * @see java.lang.SecurityException
   * @see java.lang.SecurityManager#checkLink(java.lang.String)
   */
  @CallerSensitive
  public void loadLibrary(String libname) {
    loadLibrary0(Reflection.getCallerClass(), libname);
  }

  synchronized void loadLibrary0(Class<?> fromClass, String libname) {
    SecurityManager security = System.getSecurityManager();
    if (security != null) {
      security.checkLink(libname);
    }
    if (libname.indexOf((int) File.separatorChar) != -1) {
      throw new UnsatisfiedLinkError(
          "Directory separator should not appear in library name: " + libname);
    }
    ClassLoader.loadLibrary(fromClass, libname, false);
  }

  /**
   * Creates a localized version of an input stream. This method takes
   * an <code>InputStream</code> and returns an <code>InputStream</code>
   * equivalent to the argument in all respects except that it is
   * localized: as characters in the local character set are read from
   * the stream, they are automatically converted from the local
   * character set to Unicode.
   * <p>
   * If the argument is already a localized stream, it may be returned
   * as the result.
   *
   * @param in InputStream to localize
   * @return a localized input stream
   * @see java.io.InputStream
   * @see java.io.BufferedReader#BufferedReader(java.io.Reader)
   * @see java.io.InputStreamReader#InputStreamReader(java.io.InputStream)
   * @deprecated As of JDK&nbsp;1.1, the preferred way to translate a byte stream in the local
   * encoding into a character stream in Unicode is via the <code>InputStreamReader</code> and
   * <code>BufferedReader</code> classes.
   */
  @Deprecated
  public InputStream getLocalizedInputStream(InputStream in) {
    return in;
  }

  /**
   * Creates a localized version of an output stream. This method
   * takes an <code>OutputStream</code> and returns an
   * <code>OutputStream</code> equivalent to the argument in all respects
   * except that it is localized: as Unicode characters are written to
   * the stream, they are automatically converted to the local
   * character set.
   * <p>
   * If the argument is already a localized stream, it may be returned
   * as the result.
   *
   * @param out OutputStream to localize
   * @return a localized output stream
   * @see java.io.OutputStream
   * @see java.io.BufferedWriter#BufferedWriter(java.io.Writer)
   * @see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream)
   * @see java.io.PrintWriter#PrintWriter(java.io.OutputStream)
   * @deprecated As of JDK&nbsp;1.1, the preferred way to translate a Unicode character stream into
   * a byte stream in the local encoding is via the <code>OutputStreamWriter</code>,
   * <code>BufferedWriter</code>, and <code>PrintWriter</code> classes.
   */
  @Deprecated
  public OutputStream getLocalizedOutputStream(OutputStream out) {
    return out;
  }

}
